The government’s Cobra emergency committee will meet on Thursday following Wednesday’s terror attack on the Paris office of satirical magazine Charlie Hebdo, in which 12 people, including eight journalists and two police officers, were shot dead.

Home Secretary Theresa
May will chair the meeting and ministers, police and security
advisers will attend.

Senior security officials suggest a similar attack is likely to
strike the UK.

A document from the National Counter Terrorism Security Office,
seen by the Telegraph, gave employees detailed guidance on the
best ways to hide from an attacking gunman and how to barricade
themselves in.

Security in the capital has been raised overnight, with armed
police patrolling the streets around Westminster.

Police are also understood to have visited the offices of at
least one magazine, which has previously published articles about
radical Islam. The magazine was reportedly told to lock their
doors and call the police as soon as they experienced any
trouble.

The Foreign Office website has amended its advice to UK nationals
residing in Paris.

“A number of people have been killed and injured. If you're
in Paris or the Ile-de-France area, take extra care and follow
the security advice issued by the French authorities.”

“There is a high threat from terrorism. Attacks could be
indiscriminate,” it reads.

Prime Minister David Cameron stood alongside German Chancellor
Angela Merkel, currently visiting the UK for talks, to condemn
the attacks, which he called “barbaric.” The British and
German leaders were briefed by security agencies MI5 and MI6 on
the attacks on Wednesday afternoon.

“Obviously all our thoughts are with the French people
following the barbaric attack,” said Cameron.

“We should be very clear this day that these values that we
have are not sources of weakness for us, they are sources of
strength,” the PM said.

The murders in Paris are sickening. We stand with the French
people in the fight against terror and defending the freedom of
the press.

As the manhunt for the shooters continued overnight, French Prime
Minister Manuel Valls said several people had been arrested in
connection with the attack.

Arrest warrants have been issued for Cherif Kouachi and his
brother Said, who police say are “armed and dangerous.”

Labour Party leader Ed Miliband said he stood in
“solidarity” with the people of France “against this
evil terrorist attack by people intent on attacking our
democratic way of life and freedom of speech.”

On Wednesday evening, as part of a movement of global solidarity,
hundreds of people gathered in Trafalgar Square in central London
for a silent vigil. Attendees held pens, pencils and notebooks
aloft to demonstrate what is fast becoming the motif of criticism
of the attacks: the pen is mightier than the sword.

Ian Hislop, editor of the British satirical magazine Private Eye,
expressed his sadness in a statement released yesterday.